2011-01-22

ubuntu 下挂载ipad | Mounting ipad on Ubuntu

默认情况下插上ipad会报个dbus错误。

应当安装ifuse这个包,但是官方源的目前不够新。

按ifuse官网说法,添加ppa ppa:pmcenery/ppa,更新一下就好了。




In default installation, after plugged in an ipad, a dialog will show saying something wrong with dbus.

The package ifuse would be necessary for accessing ipad, but the one in the official repository is not new enough.

According the the web page of ifuse, just to add the ppa ppa:pmcenery/ppa, then perform an upgrade.

2011-01-21

ios 游戏修改 | Cheating games in iOS

以前看网页都说是只能破解才能修改,今天发现其实不是

用iphone explorer可以看到app信息,这就够了,游戏的存档也都在这里。目前像megajump, run as hell都没问题,所以存档类的修改都ok了。

二进制不知道是不是也能修改,看样子是可以。

但是锁定变量这种修改应该就不行了吧。



It was said in several web pages that game files can be modified only in jailbroken ios, but today I found that this is not true.

We can explorer the files for apps with iphone explorer, and this is enough. I've successfully modified savegames of megajump and run as hell.

I'm not sure if we can modified the binary files of the games, seems to be ok.

But maybe we can not lock any variables.

2011-01-05

启用compiz和fglrx时的vnc问题 | Problem of vnc server with compiz and fglrx enabled

困扰了我近两年的问题。

远程连vnc回我的电脑,第一个画面能看到,鼠标也可以动,但是键盘按没反应,画面也不会再动。
一开始以为是网络问题,或者是设置了view only,但是本机上看,鼠标和键盘都得到了响应,所以只是屏幕刷新的问题。

这个问题我一直不知道原因。 但是最近新装的ubuntu,一开始是可以连得,没有问题,我还以为是更新了解决了这个问题。但是最近又不行了,我才开始想最近改了什么设置。 最后发现原来是启动了fglrx,关了radeon。 改回radeon后vnc又复活了。

于是查了一下, 果然是个bug,见https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/353126, 而且nvidia的闭源驱动也有这个问题,我以前是用的nvidia的卡,只是一直用它的驱动,所以没有发现这个问题。



A problem that has been bothering me for nearly two years.

So the problem is, when trying to remotely connect to the vnc server enabled on my computer, I can see only the first screenshot, without further update, the mouse pointer is moving, but keyboard events are not responded.
I thought at first this must be something wrong with the network, or maybe "view only" is set on the server, however on my computer I see that mouse and keyboard are working properly, so it's only the problem of screen updating.

I didn't know the reason all the time until now. Recently I have a new Ubuntu installed on my computer, in the first few days vnc server was working well, and I had thought that this problem had been solved in this new version of Ubuntu. However vnc failes again these days, and I begin trying to remember what I have changed in the system. In the end I found that I've enabled fglrx and disabled radeon. And vnc come back to alive after switching back to radeon.

Later I found that it's indeed a bug, see https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/353126, which also affects the nvidia proprietary driver. I was using nvidia cards before, but I had always been using its proprietary driver, and that's why I didn't find the cause before.

2011-01-02

ubuntu 10.10 ptrace权限的变动 | change in behavior of ptrace in ubuntu 10.10

最近有人在scanmem提交bug,说非root不能attach其他进程。当时我用的ubuntu 10.04,没能重现这个问题。最近用上10.10,发现确实有这个问题,于是考虑到是不是ubuntu的变动。简单搜了一下,在https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#ptrace%20Protection找到了原因,是10.10里故意这么设置的,目的是保护进程。

其作用的是/proc/sys/kernel/yama/ptrace_scope这个sysctl值,以前是0,ubuntu 10.10里默认是1。

于是scanmem以后需要root权限了。

而这个事情对于ubuntu是个好事情。



Recent some one has posted a bug in scanmem, that the program can no longer attach to other processes without run as root. At the moment I was still using ubuntu 10.04, where I couldn't reproduce the bug. Now I've been using 10.10 and I did confirm that bug. So I think this must be something changed in ubuntu. After a brief searching, I found the reason at https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#ptrace%20Protection, so that was changed intended, in order to protect the processes.

The key value is the sysctl value "/proc/sys/kernel/yama/ptrace_scope", which is 0 by default before, but now 1 by default.

So in the future scanmem will need to run as root.

And this is quite a good news for ubuntu.